[Edit]: This should no longer be a crash as of 4.19.2 - we should only get ensure() reports with this callstack.
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This is a common crash coming out of 4.18. Users have not provided any descriptions of their actions when the crash occurred.
Source Context
835 // Set the selected child node as the new root 836 check(ChildToPromote != nullptr); 837 Owner->SetRootComponent(ChildToPromote); 838 } 839 else // ...not the root node, so we'll promote the selected child node to this position in its AttachParent's child array. 840 { 841 // Cache our AttachParent 842 USceneComponent* CachedAttachParent = GetAttachParent(); 843 check(CachedAttachParent != nullptr); 844 845 // Find the our position in its AttachParent's child array 846 ***** const TArray<USceneComponent*>& AttachSiblings = CachedAttachParent->GetAttachChildren(); 847 int32 Index = AttachSiblings.Find(this); 848 check(Index != INDEX_NONE); 849
RESULT
Ensure.
Assertion failed: CachedAttachParent != nullptr [File:D:\Build\++UE4+Release-4.18+Compile\Sync\Engine\Source\Runtime\Engine\Private\Components\SceneComponent.cpp] [Line: 844] UE4Editor_Engine!USceneComponent::DestroyComponent() [scenecomponent.cpp:847] UE4Editor_UnrealEd!FComponentEditorUtils::DeleteComponents() [componenteditorutils.cpp:572] UE4Editor_Kismet!SSCSEditor::OnDeleteNodes() [sscseditor.cpp:5611] UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,SSCSEditor,0,TTypeWrapper<void> __cdecl() [delegateinstancesimpl.h:327] UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,SSCSEditor,0,void __cdecl() [delegateinstancesimpl.h:434] UE4Editor_Slate!FUICommandList::ConditionalProcessCommandBindings() [uicommandlist.cpp:216] UE4Editor_Slate!FUICommandList::ProcessCommandBindings() [uicommandlist.cpp:160] UE4Editor_Kismet!SSCSEditor::OnKeyDown() [sscseditor.cpp:3786] UE4Editor_Slate!<lambda_2afcd964c763e269e2d1a63f3a72f846>::operator() [slateapplication.cpp:4834] UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FBubblePolicy,FKeyEvent,<lambda_2afcd964c763e269e2d1a63f3a72f846> >() [slateapplication.cpp:234] UE4Editor_Slate!FEventRouter::RouteAlongFocusPath<FEventRouter::FBubblePolicy,<lambda_2afcd964c763e269e2d1a63f3a72f846>,FKeyEvent>() [slateapplication.cpp:216] UE4Editor_Slate!FSlateApplication::ProcessKeyDownEvent() [slateapplication.cpp:4832] UE4Editor_Slate!FSlateApplication::OnKeyDown() [slateapplication.cpp:4744] UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [windowsapplication.cpp:1560] UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [windowsapplication.cpp:2171] UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [windowsapplication.cpp:888] UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [windowsapplication.cpp:725] user32!UserCallWinProcCheckWow() user32!DispatchMessageWorker() UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [windowsplatformapplicationmisc.cpp:129] UE4Editor!FEngineLoop::Tick() [launchengineloop.cpp:3220] UE4Editor!GuardedMain() [launch.cpp:166] UE4Editor!GuardedMainWrapper() [launchwindows.cpp:134] UE4Editor!WinMain() [launchwindows.cpp:210] UE4Editor!__scrt_common_main_seh() [exe_common.inl:253] kernel32!BaseThreadInitThunk() ntdll!RtlUserThreadStart()
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-52921 in the post.